I've had a reply back from Shane and he hasn't got 2004 yet, so WR isn't yet compatible for 2004.
Once he gets it installed on his machines, he'll bring the program up to date.
However, as MS are aware of bugs in 2004, they may have held up the general release of 2004 until they are sorted.
That error message is normal when an older version of the repair program is used on a newer version of Windows.